It's just the randomness of nature, the natural (unmediated by ignorance and the mental states that are outflows from it) order of things. This is a materialist view and, as one who studied in the sciences for quite a while, it makes sense on a certain level. Of course, this is not the view that I nurture nor the view that I favor. That doesn't mean it's incorrect. It means that I need to practice a lot harder and achieve insight myself to understand these issues in greater depth. Then I'll have more than just an opinion.